The way I see/experience it, the problem is somewhat twofold. I took a deep breath and decided that I'm willing to GM in some systems, for a few one-shots. I put up an ad for the system I wanted to run/try the most and it barely generated any interest (we have the bare minimum of three, so I'll probably able to at least start the adventure). Sure, one could say "run systems that are more interesting for people" but no, sorry, I would only GM games I want to run first and foremost, so if no one wants to play them, there won't be a new GM, where I'm concerned. Sadly, to say.
I'm not the only one, of course there's an ad I applied for, I thought I was lucky to be the first, but no, the ad had been up for a week now and I'm still the only one there. These things make GMing here very difficult in some cases.